fix: resolve thread safety, dead code, and memory leak in rf_mapper.py

src/backgrounds/plugins/rf_mapper.py

@@ -70,6 +70,7 @@ def __init__(self, config: RFmapperConfig):
         self.loop = asyncio.new_event_loop()
         self.thread = threading.Thread(target=self._scan_task)
         self.running = False
+        self.scan_lock = threading.Lock()
 
         self.scan_results: List[RFData] = []
         self.scan_idx = 0
@@ -113,8 +114,6 @@ def __init__(self, config: RFmapperConfig):
 
         self.seen_devices: Dict[str, RFData] = {}
 
-        self.seen_names: List[str] = []
-
         self.start()
 
     async def scan(self) -> List[RFData]:
@@ -201,6 +200,14 @@ def detection_callback(device, advdata: AdvertisementData):
         # scan for 5 seconds, then return a new payload
         await asyncio.sleep(5.0)
         await scanner.stop()
+        # Cleanup stale BLE devices not seen for more than 60 seconds
+        now = time.time()
+        stale_addrs = [
+            addr for addr, dev in self.seen_devices.items() if now - dev.unix_ts > 60
+        ]
+        for addr in stale_addrs:
+            del self.seen_devices[addr]
+            logging.debug(f"Removed stale BLE device: {addr}")
 
         logging.debug(f"ready to sort: {self.seen_devices.values()}")
 
@@ -217,7 +224,8 @@ def detection_callback(device, advdata: AdvertisementData):
                 final_list.append(device)
         logging.debug(f"Scan...{final_list}")
 
-        self.scan_idx += 1
+        with self.scan_lock:
+            self.scan_idx += 1
 
         return final_list
 
@@ -229,7 +237,9 @@ def _scan_task(self):
         logging.info("Starting RF scan thread...")
         self.running = True
         while self.running:
-            self.scan_results = self.loop.run_until_complete(self.scan())
+            new_results = self.loop.run_until_complete(self.scan())
+            with self.scan_lock:
+                self.scan_results = new_results
             logging.info(f"RF scan index: {self.scan_idx}")
             logging.info(f"RF scan last sent: {self.scan_last_sent}")
             time.sleep(0.5)
@@ -262,11 +272,12 @@ def run(self) -> None:
                 logging.info(f"RF scan index: {self.scan_idx}")
                 logging.info(f"RF scan last sent: {self.scan_last_sent}")
                 fresh_scan_results = []
-                if self.scan_results and self.scan_idx > self.scan_last_sent:
-                    fresh_scan_results = self.scan_results
-                    self.scan_last_sent = self.scan_idx
-                    self.scan_results = []
-                    logging.info(f"RF scan sending new payload: {self.scan_last_sent}")
+                with self.scan_lock:
+                    if self.scan_results and self.scan_idx > self.scan_last_sent:
+                        fresh_scan_results = self.scan_results
+                        self.scan_last_sent = self.scan_idx
+                        self.scan_results = []
+                logging.info(f"RF scan sending new payload: {self.scan_last_sent}")
 
                 # basic gps data and occasional scan results
                 try: